watchOS 5.0 (build 16R5363a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2018-08-31T17:15:37Z. The update package is 624.6 MB. This is a delta (partial) update that requires 4.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c7833c99a7cd06ffb71bbc6872791ed767d999d0.zip.